Firearm conversion kit

ABSTRACT

A cartridge feed tray for belt ammunition is modified to receive shorter ammunition and exclude ammunition of standard length by inclusion of an insert positioned along the forward containment wall of the tray. The insert carries a feed lip that fits through a loading port orifice in the feed tray to direct shorter ammunition downwardly as it is being advanced towards the weapon breach for loading.

FIELD OF THE INVENTION

[0001] This Invention relates to the field of firearms and provisionsfor modifying automatic firearms for training purposes. In particular,it relates to automatic gas-operated weapons adapted to firereduced-energy ammunition in a blow-back mode and to training ammunitionfor use therein.

BACKGROUND TO THE INVENTION

[0002] Reduced-Energy Ammunition for Training Purposes

[0003] In military and police firearms applications almost all of theammunition consumed is used for training. For some training purposes,however, standard (service) ammunition is inappropriate. An alternativetype of training ammunition, represented by U.S. Pat. No. 5,359,937(adopted herein by reference) fires a low-mass projectile relying on atelescopically-expanding, reduced-energy cartridge designed to provideblow-back cycling of suitable modified, recoil-operated or gas-operatedautomatic weapons.

[0004] Advantages of the reduced-energy ammunition are that it has ashorter range and lower penetration capacity than standard ammunition.This permits the use of smaller, less secure firing ranges, evenimprovised ranges, as training facilities. However, if standardammunition were accidentally employed in such facilities, unexpecteddangers would arise from its increased striking power and range.

[0005] Appropriate modifications to certain semi-automatic and automaticweapons allow normal weapon functioning, including recoil, through apure blow-back action when firing such training ammunition. Such asystem, when firing low mass marking cartridges, for example, allowseffective close-range, force-on-force training. Tactical scenarios thatcan be effectively simulated include counter-terrorism, close quarterscombat, trench clearing, fighting in wooded areas, urban fighting, roomclearing, dynamic entries, and protection of dignitaries.

[0006] Confidence is gained because the training ammunition/conversionkit system allows the trainees to use their own service weapons duringstressful exercises that involve shooting and being shot at underrealistic tactical situations. The training is safe when properlyconducted, but there is a pain penalty for participants who are hit. Itis the fear of this penalty that encourages the participants to treatthe training scenarios as “the real thing” and to behave as though theirlives were at risk.

[0007] Modification to Weapon to Permit Firing of Reduced-EnergyAmmunition

[0008] When firing standard ammunition with its abundant associatedenergy, it is necessary in many weapons to lock the barrel to the slide(for pistols) or to the bolt/bolt carrier assembly (for gas-operatedrifles or machineguns) during the beginning of the firing action for aperiod long enough for the bullet to exit the barrel muzzle while thebreech is still closed. This allows the chamber pressure to drop beforethe breech opens to extract and eject the spent cartridge case. Alocking mechanism couples the barrel to the slide or bolt/bolt carrierassembly for the first portion of the discharge, and then releases theslide or bolt/bolt carrier assembly, usually with the aid of a cam. Uponunlocking, the slide or bolt/bolt carrier assembly continues itsrearward travel until, after the spent cartridge case has been ejected,it returns under the influence of the recoil spring to receive andchamber the next round from the magazine en route to its in-batteryposition.

[0009] In a training system such as described above there is not enoughenergy in the reduced-energy cartridges to precipitate sufficient recoilto unlock the barrel from the slide or bolt/bolt carrier assembly intheir standard configurations. It is necessary, therefore, to omit thebarrel locking mechanism and, by so doing, the recoil action becomesblow-back of the slide or bolt/bolt carrier assembly only.

[0010] The modifications to a semi-automatic pistol, for example, topermit normal functioning when firing reduced-energy ammunition asrepresented by U.S. Pat. No. 5,359,937 generally include replacing ormodifying the barrel and sometimes replacing or adding one or two othercomponents, depending on the weapon involved. In a gas-operated weapon,the bolt is prevented from rotating so that it will not engage the camin the barrel extension. In both instances, the modifications result ina pure blow-back action of the weapon upon firing reduced energyammunition which is sufficient to cycle the weapon in a normal fashion.

[0011] Problem of Feeding in Automatic Weapons

[0012] In some instances the external configuration of thereduced-energy ammunition is not identical to that of the equivalentstandard ammunition. This is the case with 5.56 mm reduced-energyammunition as represented by U.S. Pat. No. 5,359,937, which may beshorter and have a different weight than the standard 5.56 mm cartridge,as well as having a head end of smaller diameter.

[0013] In weapons such as, for example, the 5.56 mm Fabrique Nationale(FN) “Minimi” machinegun or the similar 5.56 mm US M249 Light SupportWeapon, linked ammunition is fed into the chamber via a feed trayfollowed by a feed ramp. Should shorter than normal ammunition, such asthe above training ammunition, be fed into the normal feed tray and saidfeed ramp, chambering of the ammunition may not proceed smoothly. Thereis the possibility of one or more cartridges skewing in the normal trayor ramp, both of which are too large to ensure the proper feeding ofsaid ammunition.

[0014] This is important in training systems utilizing reduced-energyammunition because the training projectile is often more fragile thatthe standard one. If the feeding is not true and the cartridge skewsslightly prior to entering the chamber, the tip of the projectile is notstrong enough to resist being damaged with the result that the weaponmay jam. A first objective of the present invention is, therefore, toprovide a solution to this problem by allowing the feeding andchambering of reduced-energy ammunition to proceed normally during fullautomatic firing of a machinegun such as the M249.

[0015] Problem of Live-Fire Exclusion

[0016] The conversion of 9 mm pistols to allow them to function normallywhen firing reduced-energy ammunition generally involves replacing thestandard barrel by a training barrel. To ensure that a live servicecartridge cannot be chambered in a converted weapon, the caliber of thetraining projectile and the training barrel are intentionally madesmaller than 9 mm. Hence, a live round cannot chamber properly in aweapon converted for training because its projectile is too big to fitinto the bore of the training barrel, and the weapon would jam.

[0017] The same approach could be taken for 5.56 mm gas-operatedsemi-automatic rifles and fully automatic machineguns by changing thebarrel in the upper receiver barrel assembly and altering the bolt inthe bolt carrier assembly to remove the locking mechanism. While such adesign would ensure the exclusion of live service ammunition from beingfired from a converted weapon, it would also be costly to implement andawkward for the user due to the excessive number of weapon componentsinvolved.

[0018] An alternative approach is to modify only the bolt/bolt carrierassembly, leaving untouched the upper receiver barrel assembly and thelower receiver buttstock assembly. In this way, the weapon can berapidly and conveniently converted to fire reduced-energy trainingammunition by simply exchanging the service bolt/bolt carrier assemblyfor a training bolt/bolt carrier assembly. This means, however, thatlive service ammunition would not be excluded from chambering in thestandard 5.56 mm barrel. The possibility that a standard round can befired from a converted weapon is not acceptable from a safety point ofview.

[0019] It is, therefore, a second objective of the invention to providea solution to this safety problem by preventing a live 5.56 mm cartridgefrom reaching the chamber of the standard barrel in-the upper receiverbarrel assembly of a machinegun such as the M249. By so doing, safefiring of training ammunition training in a converted weapon of thistype can be conducted while positively excluding the firing of a liveround of service ammunition should one (or more) be inadvertentlyinserted into the links feeding the weapon during training or practicesessions

[0020] The invention in its general form will first be described, andthen its implementation in terms of specific embodiments will bedetailed with reference to the drawings following hereafter. Theseembodiments are intended to demonstrate the principal of the inventionand the manner of its implementation. The invention in its broadest andmore specific forms will be further described and defined in each of theindividual claims that conclude the specification.

SUMMARY OF THE INVENTION

[0021] The invention is preferably directed to gas-operated automaticmachineguns, as typified by the M249 Light Support Weapon, that areadapted to fire reduced-training ammunition as represented by U.S. Pat.No. 5,359,937.

[0022] According to one aspect of the invention a feed tray forsupplying belt ammunition cartridges to an automatic firearm is providedthat comprises:

[0023] (a) a tray support surface

[0024] (b) forward and rearward ammunition containment side wallsmounted along opposite sides of said tray support surface

[0025] (c) a loading port orifice at the end of the forward containmentwall through which cartridges may be advanced

[0026] (d) a feed lip positioned above the loading port orifice alongthe forward containment wall, outwardly from the tray support surface

[0027] whereby ammunition being fed through such tray and outwardlythrough the loading port orifice is guided in its advancement throughsaid orifice by the feed lip. Optionally, the feed lip may be carried byan insert that is coupled to the feed tray, as by attachment to theforward ammunition containment side wall.

[0028] According to another aspect of the invention a feed tray forsupplying belt ammunition cartridges to an automatic firearm is providedthat comprises:

[0029] (a) a tray support surface

[0030] (b) forward and rearward ammunition containment side wallsmounted along opposite sides of said tray support surface- and

[0031] (c) a training cartridge guide surface located along the innerside of the forward containment wall to reduce the distance between saidcontainment walls to substantially the length of training ammunitioncartridges to be passed through said tray for firing, which cartridgesare shorter that standard ammunition in their length.

[0032] This training cartridge guide surface may be provided by athickened forward ammunition containment wall as an integral part ofsuch wall; or it may be provided by an insert coupled to such wall, asby fasteners, welding or an interfitting shape that allows the insert toengage with such wall.

[0033] As an example of an interfitting shape the insert may include awall portion with a groove positioned and dimensioned to receive andinterfit with the upper edge of the forward containment wall to fix theinsert in place on the feed tray.

[0034] Optionally, such insert may carry the feed lip for positioningabove the loading port orifice along the forward containment wall,outwardly from the tray support surface, whereby ammunition being fedthrough such tray and outwardly through the loading port orifice will beguided in its advancement through said orifice by the feed lip.

[0035] The foregoing summarizes the principal features of the inventionand some of its optional aspects. The invention may be furtherunderstood by the description of the preferred embodiments, inconjunction with the drawings, which now follow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 is a top view of a prior art feed tray for a 5.56 mm Minimior M249 automatic machinegun shown with prior art 5.56 mm linked serviceammunition being fed through it before being picked up by the bolt anddrawn down into the breech en route to the chamber.

[0037]FIG. 2 is a schematic representation of the prior art feed tray ofFIG. 1.

[0038]FIG. 3 is a side view cross-section of the prior art feed tray ofFIGS. 1 and 2 as assembled in a prior art Minimi or M249 machinegun.

[0039]FIG. 4 is the same as FIG. 3 except the bolt has moved forwardslightly to pick up the cartridge to the extent that the tip of thecartridge is entering the feed ramp of the barrel extension.

[0040]FIG. 5 is the same as FIGS. 3 and 4 except the bolt is evenfarther forward with the cartridge proceeding normally downward throughthe feed ramp of the barrel extension and into the chamber.

[0041]FIG. 6 is the same as FIGS. 3, 4 and 5 except the bolt is now inits forward most position and the cartridge is fully chambered and readyfor firing.

[0042]FIG. 7 is the same as FIG. 3 except the cartridge shown is atraining cartridge as represented by U.S. Pat. No. 5,359,937, which isshorter than the standard 5.56 mm cartridge. That is, the trainingcartridge is shown being fed into the machinegun through a prior artservice feed tray.

[0043]FIG. 8 is the same as FIG. 7 except the bolt has moved forwardslightly to pick up a training cartridge to the extent that the tip ofthe cartridge is at the entrance to the feed ramp, but not cleanlyentering onto the feed ramp.

[0044]FIG. 9 is the same as FIGS. 7 and 8 except the bolt is stillfarther forward, the cartridge has not properly entered the feed ramp,and the weapon has jammed.

[0045]FIG. 10 is a top view of a training insert of the invention forcombination with a standard feed tray.

[0046]FIG. 10A is the same representation of the feed tray as in FIG. 2except the training insert of FIG. 10 has been added. With the additionof the insert, it becomes a training feed tray.

[0047]FIG. 11 is a top view of a training feed tray for a 5.56 mm Minimior M249 automatic machinegun shown with 5.56 mm linked trainingammunition being fed through it before being picked up by the trainingbolt and drawn down into the breech en route to the chamber. Forclarity, there is no round of ammunition in the loading port, nor areempty links shown to extend over and beyond the loading port as theywould normally do during firing.

[0048]FIG. 12 is a side view cross-section of the training feed tray ofFIG. 10 as assembled in a prior art Minimi or M249 machinegun showing atraining bolt/bolt carrier assembly, a 5.56 mm training cartridge in thetraining feed tray, a prior art barrel extension and a prior art barrel.The training cartridge is shown in the training feed tray just beforebeing picked up by the training bolt for chambering.

[0049]FIG. 13 is the same as FIG. 12 except the training bolt has movedforward slightly to pick up the training cartridge to the extent thatthe tip of the training cartridge is entering the feed lip of thetraining inset.

[0050]FIG. 14 is the same as FIGS. 12 and 13 except the training bolt iseven farther forward with the training cartridge proceeding normallydownward through the feed ramp of the barrel extension.

[0051]FIG. 15 is the same as FIGS. 12, 13 and 14 except the trainingbolt is now in its forward most position and the training cartridge isfully chambered and ready for firing.

[0052]FIG. 16 is a top view of a training feed tray for a 5.56 mm Minimior M249 automatic machinegun shown with 5.56 mm linked trainingammunition being fed through it before being picked up by the trainingbolt and drawn down into the breech en route to the chamber. In the beltof ammunition leading into the feed tray, but not yet having reached it,is one 5.56 mm service cartridge. For clarity, there is no round ofammunition in the loading port, nor are empty links shown to extend overand beyond the loading port as they would normally do during a firing.

[0053]FIG. 17 is a top view of a variant of the training insert of FIG.10 redesigned with a portion with a thicker wall having a slot formed insuch thicker wall to fit over the top edge of the forward side wall ofthe tray.

[0054]FIG. 18 is a perspective view of a training feed tray fitted witha slotted insert as in FIG. 17.

[0055]FIG. 19 shows a further variant of the training feed tray of FIG.10A wherein the training feed tray and training cartridge guide surfaceis depicted in perspective view as being of one monolithic piece (i.e.,not two pieces attached together as in FIG. 10A).

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0056]FIG. 1 is the top view of a service feed tray 1 normally mountedon an FN Minimi machinegun or US M249 Light Support Weapon with a beltof service 5.56 mm ball ammunition 2 being fed through it over the traysupport surface 1A, by service links 3. Forward 4B and rearward 4Cammunition containment side walls are mounted along opposite sides ofthe tray support surface 1A. When each cartridge 2 arrives above loadingport 4 it is removed from its link 3 by the weapon's bolt (not shown)and pulled downwards through loading port 4. Links 3 are discarded tothe right of the feed tray 1. For clarity, there is no round ofammunition in the loading port, nor are empty links shown to extend overand beyond the loading port as they would normally do during firing.FIG. 2 illustrates the structure of service feed tray 1 in athree-dimensional view highlighting loading port 4, exist orifice 4A andside wall 4B.

[0057]FIG. 3 is a side view cross section of service feed tray 1 ofFIGS. 1 and 2 as assembled in a service Minimi or M249 machinegun (notshown) with a service cartridge 2 positioned directly above loading port4 (better seen in FIGS. 1 and 2). Service bolt/bolt carrier assembly 8,service bolt carrier 9, a service 5.56 mm cartridge 2 in said servicefeed tray 1, service barrel extension 6 containing feed ramp 5 andservice barrel 7 complete the assembly. Service cartridge 2 is shown infeed tray 1 occupying substantially the distance between containmentwalls 4B, 4C just before being picked up by service bolt 10 after theweapon has been fired.

[0058]FIG. 4 is the same as FIG. 3 except that service cartridge 2 hasnow been moved slightly forward by service bolt 10, as the firing cycleprogresses. Service projectile 2A of service cartridge 2 has cleanlypassed through exit orifice 4A of service feed tray 1 to enter feed ramp5 of service barrel extension 6. FIGS. 4 through 6 depict the continuedprogress of service cartridge 2 through feed ramp 5 and service barrelextension 6 until properly chambered in service barrel with service bolt10 in its forward most position ready for firing.

[0059]FIG. 7 is the same as FIG. 3 except that service cartridge 2 hasbeen replaced in service feed tray 1 by a 5.56 mm reduced energytraining cartridge 11, as represented by U.S. Pat. No. 5,359,937. Inorder to fire such training ammunition in weapons such as the FN Minimior the US M249 machineguns, it is necessary to convert the weapon topure blow back action. This is done by uncoupling the locking mechanismthat holds the service bolt/bolt carrier assembly 8 to the servicebarrel 7 and disconnecting the gas recoil system (not shown). Thus, theassembly of FIG. 7 comprises training bolt/bolt carrier assembly 14,training bolt carrier 15, training bolt 16 and training pin 17.

[0060] In this configuration, however, the distance “A” between the tipof training projectile 12 and side wall 5B of service feed tray 1 isappreciably greater than the similar distance “B” between the tip of theservice projectile 2A and said side wall 4B of said feed tray 1 in FIG.3. There is, therefore, freedom for training cartridge 11 to skewsomewhat after being removed from service link 3. As a result, whentraining bolt 16 picks up training cartridge 11, said training cartridge11 frequently does not pass cleanly through exit orifice 4A, but rathercatches on its edge 4B as depicted in FIG. 8. This results in a weaponjam, as illustrated in FIG. 9.

[0061]FIG. 10 shows a training insert 18 of the invention comprisingfeed lip 18A, curved wall 18B and straight wall 18C, the tray-sideportion of which serves as a training cartridge guide surface 18D. Theshape of said training insert 18 is such that curved wall 18B andstraight wall 18C fit snugly against the inside of side wall 4B ofservice feed tray 1 and feed lip 18A extends outwardly and downwardlythrough exit orifice 4A as depicted in FIG. 10A. Training insert 18 maybe permanently attached to service feed tray 1 in a variety ofmechanical ways to form training feed tray 19, eg as by screws, bolts orthe like. The preferred method of this invention is to weld the twopieces together. Insert 18 may also be extended forwardly along aportion of its top surface and be slotted on the underside of theextension to fit over containment wall 4B as described further below. Orit may be integrally formed with the feed tray 1 to provide the trainingcartridge guide surface 18D.

[0062]FIG. 11 is the same as FIG. 1 except that service cartridges 2have been replaced by training cartridges 11 and service feed tray 1 hasbeen replaced by training feed tray 19. In this configuration, there isno longer any space between the tip of training projectile 12 and sidewall 18C of training insert 18 for training cartridge 11 to move unduly.In addition, feed lip 18A offsets the difficulty of the shorter trainingcartridge 11 to reach feed ramp 5 by bridging the gap between existorifice 4A and the entrance to said feed ramp 5, as illustrated in FIG.12.

[0063]FIG. 12 is the same as FIG. 7 except that training feed tray 19has replaced service feed tray 1. The presence of training insert 18eliminates the possibility of excess movement of training cartridge byreducing the distance between the tip of training projectile 12 andstraight side wall 18C of training insert 18 to the minimum required forproper feeding of the linked ammunition. That is, distance “C” of FIG.12 for the firing of training ammunition is essentially the same asdistance “B” of FIG. 3 for the firing of service ammunition. This meansthat training cartridge 11 will pass unimpeded through exit orifice 4Aof training feed tray 19.

[0064] Once safely through exit orifice 4A, however, the tip of trainingprojectile 12 is too far away from the entrance to feed ramp 5 ofservice barrel extension 6 to ensure reliable chambering without thepresence of feed lip 18A of training insert 18. As shown in FIG. 13,said feed lip 18A guides training cartridge 11 so that trainingprojectile 12 cleanly enters feed ramp 5. FIGS. 14 and 15 depict thecontinued progress of training cartridge 11 through feed ramp 5 andservice barrel extension 6 until properly chambered in service barrel 7with training bolt 19 in its forward most position ready for firing.

[0065] It is, therefore, an objective of this invention to encouragenormal feeding of training cartridges 11 when fired in FN Minimi or USM249 machineguns by using training feed tray 19 in place of service feedtray 1. Preferably, said training feed tray 19 becomes an integral partof the conversion kit that permits said training cartridges to be firedreliably from said Minimi and M249 machineguns. Other components of theconversion kit include, but are not restricted to, training bolt/boltcarrier assembly 14, training bolt carrier 15, training bolt 16 andtraining pin 17.

[0066]FIG. 16 is similar to FIG. 11 except the linked ammunition, whichshould consist only of training cartridges 11, inadvertently alsocontains one service cartridge 2. If service cartridge 2 were to chamberand be fired during a force-on-force training session, for example, itcould inflict serious damage on unsuspecting targets, including humanbeings. As can be seen in FIG. 16, this cannot occur because thepresence of training insert 18 in training feed tray 19 blocks passageof service cartridge 2, such blockage leading to subsequent jamming ofthe weapon. Such a blockage will alert the user to the possibility ofother service cartridges being present as well as demanding a review ofthe safety procedures associates with the preparation of ammunitionbelts containing training ammunition.

[0067] It is, therefore, a second objective of this invention to providea live-fire exclusion mechanism during training operations withreduced-energy cartridges 11. The presence of the training feed tray 19positively prevents a service cartridge 2 from even commencing thechambering process, hence rendering the converted Minimi or M249machineguns safe to use during training sessions.

[0068]FIG. 12 is the same as FIG. 7 except that training feed tray 19has replaced service feed tray 1. The presence of training insert 18eliminates the possibility of excess movement of training cartridge byreducing the distance between the tip of training projectile 12 andstraight side wall 18C of training insert 18 to the minimum required forproper feeding of the linked ammunition. That is, distance “C” of FIG.12 for the firing of training ammunition is essentially the same asdistance “B” of FIG. 3 for the firing of service ammunition. This meansthat training cartridge 11 will pass unimpeded through exit orifice 4Aof training feed tray 19.

[0069] Once safely through exit orifice 4A, however, the tip of trainingprojectile 12 is too far away from the entrance to feed ramp 5 ofservice barrel extension 6 to ensure reliable chambering without thepresence of feed lip 18A of training insert 18. As shown in FIG. 13,said feed lip 18A guides training cartridge 11 so that trainingprojectile 12 cleanly enters feed ramp 5. FIGS. 14 and 15 depict thecontinued progress of training cartridge 11 through feed ramp 5 andservice barrel extension 6 until properly chambered in service barrel 7with training bolt 19 in its forward most position ready for firing.

[0070] It is, therefore, an objective of this invention to encouragenormal feeding of training cartridges 11 when fired in FN Minimi or USM249 machineguns by using training feed tray 19 in place of service feedtray 1. Thus, said training feed tray 19 becomes an integral part of theconversion kit that permits said training cartridges to be firedreliably from said Minimi and M249 machineguns. Other components of theconversion kit include, but are not restricted to, training bolt/boltcarrier assembly 14, training bolt carrier 15, training bolt 16 andtraining pin 17.

[0071]FIG. 16 is a similar to FIG. 11 except the linked ammunition,which should consist only of training cartridges 11, inadvertently alsocontains one service cartridge 2. If service cartridge 2 were to chamberand be fired during a force-on-force training session, for example, itcould inflict serious damage on unsuspecting targets, including humanbeings. As can be seen in FIG. 16, this cannot occur because thepresence of training insert 18 in training feed tray 19 blocks passageof service cartridge 2, such blockage leading to subsequent jamming ofthe weapon. Such a blockage will alert the user to the possibility ofother service cartridges being present as well as demanding a review ofthe safety procedures associated with the preparation of ammunitionbelts containing training ammunition.

[0072] It is, therefore, a second objective of this invention to providea live-fire exclusion mechanism during training operations withreduced-energy cartridges 11. The presence of the training feed tray 19positively prevents a service cartridge 2 from even commencing thechambering process, hence rendering the converted Minimi or M249machineguns safe to use during training sessions.

[0073]FIGS. 17 and 18 depict a further variant of the invention whereinthe insert 18 has a widened curved portion 18B which has a slot 20 onits underside surface. This slot 20 fits over the curved portion 21 ofthe front containment wall 4B and holds the insert 18 in place.

[0074]FIG. 19 shows a monolithic training tray 22 with the trainingcartridge guide surface 18D formed as part of the tray 22 itself.

[0075] Training feed tray 19 of FIG. 16 has been tested successfullymany times in an M249 machinegun converted to fire reduced-energytraining cartridges as represented by U.S. Pat. No. 5,359,937. It isalso adaptable to other similar weapons, including the FN minimi.

CONCLUSION

[0076] The foregoing has constituted a description of specificembodiments showing how the invention may be applied and put into use.These embodiments are only exemplary. The invention in its broadest, andmore specific aspects, is further described and defined in the claimswhich now follow. These claims, and the language used therein, are to beunderstood in terms of the variants of the invention which have beendescribed. They are not to be restricted to such variants, but are to beread as covering the full scope of the invention as is implicit withinthe invention and the disclosure that has been provided herein.

The embodiments of the invention in which and exclusive property orprivilege is claimed are defined as follows:
 1. A feed tray forsupplying belt ammunition training cartridges to an automatic firearmsuited to fire standard cartridges of standard length comprising: (a) atray support surface (b) forward and rearward ammunition containmentside walls mounted along opposite sides of said tray support surface (c)a loading port orifice at the end of the forward containment wallthrough which cartridges may be advanced characterized by a feed lipwith a guide surface positioned above the loading port orifice along theforward containment wall which feed lip protrudes outwardly from theforward containment wall to downwardly guide training ammunition passingthrough the loading port orifice, whereby training ammunition of shorterlength than standard length ammunition being fed through such tray andoutwardly through the loading port orifice is guided in its advancementthrough said orifice by the feed lip.
 2. A feed tray as in claim 1wherein the forward containment wall has an outer side characterized inthat the guide surface of the feed lip extends rearwardly from the outerside of the forward containment wall to provide an extended guidesurface. ammunition cartridges to be passed through said tray for firingwhich cartridges are shorter than the standard ammunition in theirlength.
 3. A tray as in claim 2 wherein the training cartridge guidesurface is provided by an insert that attached in place on the tray. 4.A tray as in claim 3 wherein the forward ammunition containment sidewall has an upper edge and the insert comprises a groove positioned anddimensioned to receive the upper edge of said containment side wall tofix the insert in place on the feed tray.
 5. A tray as in claim 2comprising: (a) a loading port orifice at the end of the forwardcontainment wall through which cartridges may be advanced (b) a feed lippositioned above the loading port orifice along the forward containmentwall, outwardly from the tray support surface whereby ammunition beingfed through such tray and outwardly through the loading port orifice isguided in its advancement through said orifice by the feed lip.
 6. Atray as in claim 5 wherein the feed lip is carried by and supported inits position by the insert.
 7. A tray as in claim 3 comprising: (a) aloading port orifice at the end of the forward containment wall throughwhich cartridges may be advanced (b) a feed lip positioned above theloading port orifice along the forward containment wall, outwardly fromthe tray support surface whereby ammunition being fed through such trayand outwardly through the loading port orifice is guided in itsadvancement through said orifice by the feed lip.
 8. A tray as in claim7 wherein the feed lip is carried by and supported in its position bythe insert.
 9. A tray as in claim 4 comprising: (a) a loading portorifice at the end of the forward containment wall through whichcartridges may be advanced (b) a feed lip positioned above the loadingport orifice along the forward containment wall, outwardly from the traysupport surface whereby ammunition being fed through such tray andoutwardly through the loading port orifice is guided in its advancementthrough said orifice by the feed lip.
 10. A tray as in claim 6 whereinthe feed lip is carried by and supported in its position by the insert.